A novel approach for quantitative importance analysis of safety DI&C systems in the nuclear field

https://doi.org/10.1016/j.ress.2022.108765Get rights and content
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Abstract

As the digitalization of the safety instrumentation and control (I&C) systems in the nuclear field causes very complex interactions between their components and difficulty in securing quantitative failure information of each component, there are considerable challenges in analyzing them via probabilistic safety assessment (PSA), the typical safety analysis framework of existing safety I&C systems. This study proposes a new approach to resolve these challenges. The suggested method develops a system model based on the systems-theoretic accident model and processes (STAMP) philosophy and assigns weights to specific components according to design information and operation strategies instead of quantitative failure information. Based on the assigned weights, the importance of each component is derived by calculating the effect of a single component failure on the overall I&C functions. The methodology is explained through simple examples and validated with an analysis of a real-world system. The proposed approach is expected to be useful in deriving insights from the design stages to the improvement stages for more diverse I&C systems by enabling quantitative importance analysis without failure information.

Keywords

STAMP
Importance analysis
DI&C
PSA
Quantitative analysis
Nuclear safety

Abbreviation

APS
alternative protection system
CA
control action
CTL
control
DEC
decision
DPS
diverse protection system
DI&C
digital I&C
FB
feedback
FT
fault tree
FTA
fault tree analysis
HRA
human reliability assessment
HEP
human error probability
PSF
performance shaping factor
I&C
instrumentation and control
IM
importance
INS
instrumentation
IPS
information processing system
M
mission
MCS
minimal cut set
PSAMS
post-accident monitoring system
PC
physical control
PSA
probabilistic safety assessment
RPS
reactor protection system
SF
signal flow
STAMP
systems-theoretic accident model and processes

Data availability

  • No data was used for the research described in the article.

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